Abstract
Hormonal control of axillary bud growth has been extensively studied for many years. In particular, an involvement of two hormones, auxin and cytokinin, has been well known. On the other hand, recent genetic and physiological analysis using grafting techniques revealed that a graft transmissible branch inhibiting hormone plays a major role in the control of shoot branching. The chemical nature of the predicted branch inhibiting hormone was revealed recently.
Five tillering dwarf (d) mutants of rice, dwarf3 (d3), d10, d14, d17 and d27 , show an accelerated shoot branching and a reduced plant height in common due to the failure in biosynthesis, perception or signal transduction of strigolactone. fine culm1 (fc1) mutant also shows an increased shoot branching, resembling the five d mutants. FC1 is an ortholog of maize teosinte branched1 (tb1) , and encodes a transcription factor containing a TCP domain.
As a first step to reveal how strigolacton controls shoot branching, we analyzed phenotypes of the five d mutants and fc1 in detail. Moreover, a possible interaction between FC1 and strigolactone will be discussed.
